More informative error for passing a list to dataset.transpose

[patrick-naylor]

Closes #6502

• Closes #xxxx
• Tests added
• User visible changes (including notable bug fixes) are documented in whats-new.rst
  - [ ] New functions/methods are listed in api.rst

[max-sixty]

Thank you v much @patrick-naylor

[max-sixty]

Here's a fix of the type checker and a small suggestion (feel free to accept or reject!)

commit 5dad26e19f1fb22e9a31854bac9471c5e1bec43c
Author: Maximilian Roos <m@maxroos.com>
Date:   Tue Oct 4 00:26:48 2022 -0700

    Ignore type on intentional error; (optional) tweak to error message

diff --git a/xarray/core/dataset.py b/xarray/core/dataset.py
index ff54bd84..a3f26d26 100644
--- a/xarray/core/dataset.py
+++ b/xarray/core/dataset.py
@@ -5405,7 +5405,7 @@ def transpose(
         if (len(dims) > 0) and (isinstance(dims[0], list)):
             list_fix = [f"'{x}'" if isinstance(x, str) else f"{x}" for x in dims[0]]
             raise TypeError(
-                f'transpose requires dims to be passed as multiple arguments. Expected "{", ".join(list_fix)}". Received "{dims[0]}" instead'
+                f'transpose requires dims to be passed as multiple arguments. Expected `.transpose({", ".join(list_fix)})`. Received `.transpose({dims[0]})` instead'
             )
 
         # Use infix_dims to check once for missing dimensions
diff --git a/xarray/tests/test_dataset.py b/xarray/tests/test_dataset.py
index 6ac5ed06..8acd3798 100644
--- a/xarray/tests/test_dataset.py
+++ b/xarray/tests/test_dataset.py
@@ -6809,7 +6809,7 @@ def test_string_keys_typing() -> None:
     ds.assign(variables=mapping)
 
 
-def test_traspose_error() -> None:
+def test_transpose_error() -> None:
     # Transpose dataset with list as argument
     # Should raise error
     ds = xr.Dataset({"foo": (("x", "y"), [[21]]), "bar": (("x", "y"), [[12]])})
@@ -6817,7 +6817,7 @@ def test_traspose_error() -> None:
     with pytest.raises(
         TypeError,
         match=re.escape(
-            "transpose requires dims to be passed as multiple arguments. Expected \"'y', 'x'\". Received \"['y', 'x']\" instead"
+            "transpose requires dims to be passed as multiple arguments. Expected `.transpose('y', 'x')`. Received `.transpose(['y', 'x'])` instead"
         ),
     ):
-        ds.transpose(["y", "x"])
+        ds.transpose(["y", "x"])  # type: ignore

[patrick-naylor]

Thanks @max-sixty

Here's a fix of the type checker and a small suggestion (feel free to accept or reject!)

commit 5dad26e19f1fb22e9a31854bac9471c5e1bec43c
Author: Maximilian Roos <m@maxroos.com>
Date:   Tue Oct 4 00:26:48 2022 -0700

    Ignore type on intentional error; (optional) tweak to error message

diff --git a/xarray/core/dataset.py b/xarray/core/dataset.py
index ff54bd84..a3f26d26 100644
--- a/xarray/core/dataset.py
+++ b/xarray/core/dataset.py
@@ -5405,7 +5405,7 @@ def transpose(
         if (len(dims) > 0) and (isinstance(dims[0], list)):
             list_fix = [f"'{x}'" if isinstance(x, str) else f"{x}" for x in dims[0]]
             raise TypeError(
-                f'transpose requires dims to be passed as multiple arguments. Expected "{", ".join(list_fix)}". Received "{dims[0]}" instead'
+                f'transpose requires dims to be passed as multiple arguments. Expected `.transpose({", ".join(list_fix)})`. Received `.transpose({dims[0]})` instead'
             )

This is what I initially had but I thought it might be confusing for users passing something to missing_dims

-def test_traspose_error() -> None:
+def test_transpose_error() -> None:
     # Transpose dataset with list as argument
     # Should raise error
     ds = xr.Dataset({"foo": (("x", "y"), [[21]]), "bar": (("x", "y"), [[12]])})
@@ -6817,7 +6817,7 @@ def test_traspose_error() -> None:
     with pytest.raises(
         TypeError,
         match=re.escape(
-            "transpose requires dims to be passed as multiple arguments. Expected \"'y', 'x'\". Received \"['y', 'x']\" instead"
+            "transpose requires dims to be passed as multiple arguments. Expected `.transpose('y', 'x')`. Received `.transpose(['y', 'x'])` instead"
         ),
     ):
-        ds.transpose(["y", "x"])
+        ds.transpose(["y", "x"])  # type: ignore

This is very helpful thank you!

[max-sixty]

Thanks a lot @patrick-naylor !